<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
	<head>
		<meta charset="UTF-8">
		<title>登录界面</title>
		<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1">
	    <!--basic_css-->
	    <link rel="stylesheet" th:href="@{/layui/css/layui.css}"  media="all">

	   <style type="text/css">
    	body {
    		  background-image:url('../img/lg-bg.jpg');
    	      background-position:14px 14px;
     	      background-repeat:no-repeat;
     	      background-position: center center;
     	      background-attachment: fixed;
     	      background-size: cover;
    	}
		.layui-input{
			height:45px;
			width:87%; 
			padding-left: 5px;
			font-size:16px;
			display:inline-block;
		}
		
		.layui-btn {
			height:45px;
		}
		.captcha-input {
			height:45px; 
			padding-left: 5px;
			font-size:16px;
		}
		
		.layui-form {
			width:30%;
			height:60%;
			margin:0 auto;
			margin-top:7%;
			padding:15px 28px 0px;
			background:#fff;
		}

		.layui-input-block {
			margin-left:0;
		}
		
		.layui-input-block a {
			color:blue;
			float:right;
			line-height:30px;
			font-size:14px;
		}
		
		h1 {
			text-align:center;
			color:#1d598e;
		}
		
		input.text{
			text-align:center;
			padding:10px 20px;
			width:300px;
		}
		
		#canvas {
		float:right;
		margin-right:1%;
        display: inline-block;
        border: 1px solid #ccc;
        border-radius: 5px;
        cursor: pointer;
        }
        .code {
        width: 400px;
        margin: 0 auto;
        }
        .input-val {
        width: 60%;
        background: #ffffff;
        height: 2.8rem;       
        border-radius: 5px;
        border: none;
        border: 1px solid rgba(0,0,0,.2);
     }		
    </style>
	</head>
	
	<body>
		<form class="layui-form" th:action="@{login}" id="loginForm">
		<div class="layui-form-item">
			<h1>图书后台管理系统</h1>
		</div>
		<div class="layui-form-item">
		    <div class="layui-input-block">
				<span class="decrib">账号：</span>
				<input type="text" name="usercode" placeholder="请输入账号" autocomplete="off" class="layui-input" autofocus required>
		    </div>
		</div>
		
		<div class="layui-form-item">
			<div class="layui-input-block">
				<span class="decrib">密码：</span>
				<input type="password" name="password" placeholder="请输入密码" autocomplete="off" class="layui-input" required>
			</div>
		</div>
		
		
		<div class="layui-form-item">
			<div class="layui-input-block">
				<span class="decrib">验证码：</span>
				<input type="text" value="" placeholder="请输入验证码" class="input-val">
				<canvas id="canvas" width="88" height="43"></canvas>
			</div>
		</div>
	
				
		<div class="layui-form-item">
			<div class="layui-input-block">
				<button class="layui-btn layui-btn-fluid" id="submit">登 录</button>
			</div>
		</div>
		<br>
		<br>
	 </form>
  </body>


<!--
	描述：验证码部分代码
-->
<script th:src="@{/layui/layui.js}"></script>
<script th:src="@{/layui/jquery.min.js}"></script>
<!--验证码-->
<script>
    $(function(){
        var show_num = [];
        draw(show_num);
 
        $("#canvas").on('click',function(){
            draw(show_num);
        })
        $(".btn").on('click',function(){
            var val = $(".input-val").val().toLowerCase();
            var num = show_num.join("");
            if(val==''){
                alert('请输入验证码！');
            }else if(val == num){
                alert('提交成功！');
                $(".input-val").val('');
                draw(show_num);
 
            }else{
                alert('验证码错误！请重新输入！');
                $(".input-val").val('');
                draw(show_num);
            }
        })
    })
 
    function draw(show_num) {
        var canvas_width=$('#canvas').width();
        var canvas_height=$('#canvas').height();
        var canvas = document.getElementById("canvas");//获取到canvas的对象，演员
        var context = canvas.getContext("2d");//获取到canvas画图的环境，演员表演的舞台
        canvas.width = canvas_width;
        canvas.height = canvas_height;
        var sCode = "A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
        var aCode = sCode.split(",");
        var aLength = aCode.length;//获取到数组的长度
        
        for (var i = 0; i <= 3; i++) {
            var j = Math.floor(Math.random() * aLength);//获取到随机的索引值
            var deg = Math.random() * 30 * Math.PI / 180;//产生0~30之间的随机弧度
            var txt = aCode[j];//得到随机的一个内容
            show_num[i] = txt.toLowerCase();
            var x = 10 + i * 20;//文字在canvas上的x坐标
            var y = 20 + Math.random() * 8;//文字在canvas上的y坐标
            context.font = "bold 23px 微软雅黑";
 
            context.translate(x, y);
            context.rotate(deg);
 
            context.fillStyle = randomColor();
            context.fillText(txt, 0, 0);
 
            context.rotate(-deg);
            context.translate(-x, -y);
        }
        for (var i = 0; i <= 5; i++) { //验证码上显示线条
            context.strokeStyle = randomColor();
            context.beginPath();
            context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
            context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
            context.stroke();
        }
        for (var i = 0; i <= 30; i++) { //验证码上显示小点
            context.strokeStyle = randomColor();
            context.beginPath();
            var x = Math.random() * canvas_width;
            var y = Math.random() * canvas_height;
            context.moveTo(x, y);
            context.lineTo(x + 1, y + 1);
            context.stroke();
        }
    }
 
    function randomColor() {//得到随机的颜色值
        var r = Math.floor(Math.random() * 256);
        var g = Math.floor(Math.random() * 256);
        var b = Math.floor(Math.random() * 256);
        return "rgb(" + r + "," + g + "," + b + ")";
    }
</script>

</html>
